The "balance of nature" metaphor has been used to explain the functioning of natural systems from ancient times and continues to be invoked in popular culture, in spite of controversy regarding its use in the scientific community. We demonstrate that undergraduate students in the United States believe this term is descriptive of real ecological systems, and continue to do so after instruction in ecological science. A content analysis of students' definitions of the "balance of nature" and its causes varied widely with multiple, often contradictory, interpretations. A second survey confirmed that the range of definitions generated by students was representative of the larger educated population. Common responses included population regulation, species interactions, absence of disturbance and Nature. We speculate that the lack of a fixed meaning for the balance of nature term could lead to problems in education, public policy, and the transmission of ecological concepts to the general public. © SAGE Publications.